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morfrain_encilgar
Saturday, May 21st, 2005, 06:56 PM
Great white shark evolution debate

A significant debate is currently underway in the scientific community over the evolution of the Great White shark, and Chuck Ciampaglio, Ph.D., an assistant professor of geology at the Wright State University Lake Campus, is right in the middle of it.

The issue is if the Great White, one of the most feared predators of the sea, evolved from the huge prehistoric megalodon shark or if its ancestry rests with the mako shark.

“Most scientists would probably say the Great Whites evolved from the megalodon line, which existed from two million to twenty million years ago. They were huge sharks, approximately the length of a Greyhound bus and possessing teeth that were up to six inches long,” explains Ciampaglio. “However, our research, which is based on analyzing fossils of several hundred shark teeth, shows that the Great White shares more similarities with the mako shark.” He added that because sharks regularly replace their teeth, it is relatively easy to obtain tooth samples through fossil field work along the Atlantic seaboard.

Ciampaglio acknowledges that people seem to have a fascination with sharks. “The general public seems to like sharks, and maybe this is because they bring out the fears of our childhood, when they were perceived as scary monsters,” he explained.

His interest in sharks is apparent when entering his office. The door and walls have pictures of shark teeth, and there are posted references to fossils and a geological time table.

The research scientist makes imprints of the teeth, then digitizes the picture to establish grids of different combinations that are analyzed by a sophisticated computer program. He even uses an electron microscope to view different serration designs of shark teeth.

“Our analysis of their teeth shows that Great White and mako sharks have very similar tooth growth trajectories, while those of the great white and megalodon are not similar. Analysis of both the root and entire tooth also shows a remarkable similarity in all four tooth positions under study for both the Great White and mako shark. Serration densities possess a strong similarity between the Great White and makos, where the serration densities between the Great White and megalodon exhibit sharp differences. In summary, our morphological (form and structure) evidence strongly supports the theory that the Great White is descended from the prehistoric mako group.”

Ciampaglio said the Great White sharks, which can reach a size of nearly 25 feet and possess two-inch teeth, have been a major research subject of his for the past four years. He holds a doctorate from Duke in paleontology, the study of prehistoric life forms. His academic background also includes master’s degrees in zoology and geology and a bachelor’s degree in physics and chemistry. “My work looks at large scale changes of life over time and how things like mass extinction affect the course of life,” he said.

Ciampaglio discussed his shark research findings at recent Geological Society of America meetings in Mississippi and Colorado. A scholarly journal article on the subject is pending.

The geologist joined the Lake Campus faculty two years ago, and one of the reasons he selected Wright State was the extensive opportunity for fossil research in this region of Ohio.

Vanir
Saturday, May 21st, 2005, 07:17 PM
I've seen a Great White briefly in about 60ft of water when spearfishing at Cape Schank when I was 17.
I can laugh about it now, but basically every cell in my body was screaming out in terror. Luckily we were already on our way back in, and close to the shore. We basically walked on water! If you were in the water and saw one, you'd quickly understand what I am talking about.

That is very interesting to read the relationship with the Mako, and surprising.
Makos are utterly psychotic. My friend hooked one and is took 500 metres of 24kg line in about 15 seconds. They jump out of the water and into people's boats! About 2 or 3 months ago in the local paper here, there was a report of a fisherman who was reeling in a fish off Mornington, and as it approached the surface a Mako (which must've been following the hooked fish) speared up out of the water and rammed into him, wounding him before falling back into the water...
Also, some people think that Megalodon is still swimming around out there somewhere (which tickles my imagination I must admit) There are a few tales floating around about sightings of sharks 30 metres or so long in the early 1900's by Tuna fishermen off Eden in NSW.

But that's enough rambling....

Vanir
Saturday, May 21st, 2005, 07:22 PM
I thought no-one would believe me, so I had a quick look and managed to find a news report of it. An angry "Noah's Ark" or what!?

http://www.morningtononline.com/blog/more.php?id=65_0_1_0_M


A short shark shock in the face

A FISHERMAN got the shock of his life when a shark
leapt from the water and hit him in the face as he
reeled in a snapper in Port Phillip Bay.

Chris Bourke of Mt Martha said he was lucky to be alive
after the 2.5m shark came out of nowhere and knocked
him to the other side of the boat.
His wife, Karin, watched in horror as the shark hit the roof
of the boat and fell back into the sea.

Mr Bourke was fishing about 400m off Fisherman's Beach
at Mornington last month when the shark jumped out at him.

He described the impact as similar to being punched by a fist.

"I had a snapper on my line and got it within 3m of the boat
and out of nowhere I got hit on the side of the face," he said.

"My wife looked and saw the shark over the rocket launcher
(top of the boat) and it was looking down on her.

"The only reason it didn't land in the boat is because it hit me.
If it had have come in the boat, we would have been gone."

Mr Bourke said the boat was damaged and
"black markings and skin were left everywhere".

Mr Bourke believes it was a mako, an aggressive shark
commonly known by anglers as "psychotic".

Mornington fisheries officer Rod Barber agreed it was more
than likely a mako and described it as a fast and powerful shark.

"If you get a mako in the boat, they are so powerful,
it would do an incredible amount of damage," he said.
"It's a remarkable story - what unfolded was amazing."

Mr Barber said it was an isolated incident.

"It's a once-in-a-lifetime event for that man," he said.

Ewergrin
Sunday, May 22nd, 2005, 04:23 PM
Is tooth development the only relative connection between the Great White and the Mako shark? Forgive my ignorance, but what is the point of tracing roots back to a shark that not only exists, but flourishes today? Certainly the Mako shark cannot be an ancestor, but a sibling of the Great White?

Ewergrin
Sunday, May 22nd, 2005, 04:24 PM
http://www.securefishingstore.com/site/images/world_record/world_mako_shark.jpg

Judging by pictures like this, it would be easy to make a connection between the Great White and the Mako.

morfrain_encilgar
Monday, May 23rd, 2005, 07:54 AM
Is tooth development the only relative connection between the Great White and the Mako shark?

No, the mako is a member of the Lamnidae like the great white shark.

There is disagreement over the interrelationships within this family. The problem is that teeth are subject ot paralellism because of function, so a shark which starts to eat more large prey evolves serrated teeth like the great white shark has.